/*
 * Copyright 2002-2007 the original author or authors.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
package org.enterprisepower.io;

import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;

import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;

/**
 * IO related static utilties methods are defined in this class.
 * 
 * @author Kenneth Xu
 * 
 */
public final class IOUtils {

    private static final Log log = LogFactory.getLog(IOUtils.class);
    public static final int BUF_SIZE = 1024;

    private IOUtils() {
    }

    /**
     * Read everything from <code>in</code> and write to <code>out</code> until
     * reachs the end of the input stream. Both <code>in</code> and
     * <code>out</code> are then quitely closed (see {@link #close(InputStream)}
     * ).
     *
     * @param in
     *            data copy from
     * @param out
     *            data copy to
     * @throws IOException
     *             IO error occured when coping.
     * @see #copyStream(InputStream, OutputStream, boolean)
     */
    public static void copyStream(InputStream in, OutputStream out)
            throws IOException {
        copyStream(in, out, true);
    }

    /**
     * Read everything from <code>in</code> and write to <code>out</code> until
     * reachs the end of the input stream. If <code>closeOnFinish</code> is
     * <code>true</code>, it quitely closes both <code>in</code> and
     * <code>out</code> (see {@link #close(InputStream)}) before retun.
     * Otherwise, it leaves both of them open.
     *
     * @param in
     *            data copy from
     * @param out
     *            data copy to
     * @param closeOnFinish
     *            passing <code>true</code> to close both stream before method
     *            return
     * @throws IOException
     *             IO error occured when coping.
     * @see #copyStream(InputStream, OutputStream)
     */
    public static void copyStream(InputStream in, OutputStream out,
            boolean closeOnFinish) throws IOException {
        byte[] buf = new byte[BUF_SIZE];
        int count;
        try {
            while ((count = in.read(buf)) != -1) {
                out.write(buf, 0, count);
            }
        } finally {
            if (closeOnFinish) {
                close(in);
            }
            if (closeOnFinish) {
                close(out);
            }
        }
    }

    /**
     * Quietly close a {@linkplain java.io.InputStream}. Exceptions are
     * discarded.
     *
     * @param in
     *            the input stream to close
     * @see #close(InputStream, boolean)
     */
    public static void close(InputStream in) {
        close(in, false);
    }

    /**
     * Quietly close a {@linkplain java.io.InputStream} without throwing any
     * exception. Exceptions will be logged as error if the
     * <code>logError</code> is <code>true</code>.
     *
     * @param in
     *            the input stream to close
     * @param logError
     *            true to log exception as error
     * @see #close(InputStream)
     * @see #close(OutputStream, boolean)
     */
    public static void close(InputStream in, boolean logError) {
        if (in != null) {
            try {
                in.close();
            } catch (Throwable t) {
                if (logError) {
                    log.error(t.getMessage(), t);
                } else {
                    log.debug(t.getMessage(), t);
                }
            }
        }
    }

    /**
     * Quietly close a {@linkplain java.io.OutputStream}. Exceptions are
     * discarded.
     *
     * @param out
     *            the output stream to close
     * @see #close(OutputStream, boolean)
     */
    public static void close(OutputStream out) {
        close(out, false);
    }

    /**
     * Quietly close a {@linkplain java.io.OutputStream} without throwing any
     * exception. Exceptions will be logged as error if the
     * <code>logError</code> is <code>true</code>.
     *
     * @param out
     *            the output stream to close
     * @param logError
     *            true to log exception as error
     * @see #close(OutputStream)
     * @see #close(InputStream, boolean)
     */
    public static void close(OutputStream out, boolean logError) {
        if (out != null) {
            try {
                out.close();
            } catch (Throwable t) {
                if (logError) {
                    log.error(t.getMessage(), t);
                } else {
                    log.debug(t.getMessage(), t);
                }
            }
        }
    }
}
